//#define _CRT_SECURE_NO_WARNINGS 1
//#include<iostream>
//#include<cmath>
//using namespace std;
//class Point;
//class PointMange
//{
//public:
//	double PointDistance(Point& p1, Point& p2);
//};
//class Point
//{
//private:
//	int x;
//	int y;
//public:
//	//friend double PointDistance(Point& p1, Point& p2);
//	friend double PointMange::PointDistance(Point& p1, Point& p2);
//	Point(int x, int y)
//	{
//		this->x = x;
//		this->y = y;
//	}
//
//};
//double PointMange::PointDistance(Point& p1, Point& p2)
//{
//	double dis = (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
//	return sqrt(dis);
//}
////double PointDistance(Point& p1, Point& p2)
////{
////	double dis = (p1.x - p2.x) * (p1.x - p2.x) + (p1.y - p2.y) * (p1.y - p2.y);
////	return sqrt(dis);
////}
//
//int main()
//{
//	Point p1(1, 2);
//	Point p2(1, 0);
//	PointMange p3;
//	
//	cout << p3.PointDistance(p1, p2) << endl;
//	//cout << PointDistance(p1, p2) << endl;
//	return 0;
//}